Plug neck for a filler neck of a fuel tank

ABSTRACT

A plug neck for a filler neck of a motor vehicle has exchanging means for refueling-venting adaptation to different refueling devices. In the case of a refueling device which removes gases from a refueling channel by suction, a compensation chamber is connected permanently to the refueling channel via a connecting channel. For adaptation to a refueling device without suction removal, the connecting channel is closed and the vent valve is provided with a cap which has a connection neck for a line leading to an activated carbon filter. This allows tool costs for producing the plug neck to be kept particularly low.

FIELD OF THE INVENTION

The invention relates to automotive fuel tanks and specifically to aplug neck for a filler neck of a fuel tank of a motor vehicle having aflap which is arranged in a refueling channel which can be moved duringrefueling and is intended for switching a vent valve.

DESCRIPTION OF THE RELATED ART

Fuel tank plug necks are known for preventing the escape of fuel vaporsduring refueling and for pressure equalization with the surroundingsduring operation. At the end which is directed away from the fillerneck, the plug neck bears a fuel-tank closure cover. In the operatingposition, the second compensation chamber, for the overflow of air inthe vent valve, is connected to the refueling channel. During refueling,the flap is opened via a rocker lever and adjusts the vent valve into aposition in which it closes the second compensation chamber. Duringrefueling, air located in the fuel tank is discharged via the firstcompensation chamber.

It is necessary for the plug neck to be adapted for respectiverequirements which are to be met by the refueling venting when differentrefueling devices are used. For example, in the case of refuelingdevices which remove gases from the refueling channel by suction, it isnecessary for the vent valve to connect the first compensation chamberto the refueling channel. In the case of refueling devices withoutsuction removal, the first compensation tank has to be connected to anactivated carbon filter. For the different refueling devices, differentplug necks, which each require separate tools to produce them, have beenused. This results, in particular in the case of mass production, invery cost-intensive production of the plug neck.

SUMMARY OF THE INVENTION

The present invention provides a plug neck of the type mentioned in theintroduction such that it is particularly cost-effective to produce inparticular in mass production. This is achieved by exchanging means forthe optional connection of the first compensation chamber to a filter orthe refueling channel.

This configuration means that all that is necessary for adapting theplug neck to the respective refueling device is to replace theexchanging means. This makes it possible for the plug neck according tothe invention to be adapted to the envisaged application case with lowstructural outlay. Since the plug neck comprises the same components,with the exception of the exchanging means, for the two applicationcases, costs for storage and production of the plug neck according tothe invention are kept particularly low.

According to an advantageous development of the invention, theexchanging means for connecting the first compensation chamber to thefilter are of particularly cost-effective configuration if they have acap with a connection neck for a line leading to the filter. Since thevent valve usually requires a cap anyway for the installation of aclosure body located in the interior, this configuration does not resultin an increase in the number of the components of the plug neckaccording to the invention.

The exchanging means for connecting the first compensation chamber tothe refueling channel require particularly low structural outlay if theyhave connecting channel, which can be closed by an insert, between thefirst compensation chamber and the refueling channel. In the case of thevent valve being produced from plastic by injection molding, theconnecting channel can easily be optionally released or closed by aninsert which is to be positioned in the injection mold.

The closure element could be connected to the flap, for example, via alever arrangement. The plug neck may be adapted for different spaceconditions with particularly low structural outlay, however, if aclosure element of the vent valve is prestressed against an eccentricwhich can be moved by the flap. As a result, with an appropriateconfiguration of the eccentric, the vent valve may be arranged atvirtually any desired angle to the flap.

The vent valve could have connection necks for a plurality of linesrouted to the compensation chambers. This would require at least fourconnections and thus high installation outlay for the vent valve.However, the plug neck according to the invention can be installedparticularly easily if the vent valve has a common flange for theconnection to flanges of the two compensation chambers and of the fillerneck. In addition, this means that only two sealing locations arenecessary as a result, so that diffusion of fuel vapors from the plugneck is kept particularly low.

The connecting channel is particularly easily accessible, for adaptationto the respective application case of the plug neck according to theinvention, if it is arranged in the outside of the vent valve and can beclosed by a covering. The invention means that only two differentcoverings are necessary for the respective location case.

The plug neck according to the invention is configured particularlycost-effectively if the connecting channel is configured as a depressionin the flange. In addition, this further reduces the number of thesealing locations accessible from outside the plug neck. According toanother advantageous development of the invention, the plug neck may beconfigured in order to receive all the connections for the fuel tank ifit has a connection for a roll-over valve. This considerably simplifiesinstallation of the fuel tank in the motor vehicle.

The invention permits numerous embodiments. In order further to clarifyits basic principle, two of these are explained hereinbelow and areillustrated in the drawing, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a filler neck with a plug neck according to theinvention and with adjacent components of a fuel tank;

FIG. 2 illustrates a view from above of the plug neck according to theinvention from FIG. 1;

FIG. 3 illustrates a sectional illustration through the plug neck fromFIG. 2 along line III—III during operational venting;

FIG. 4 illustrates an offset section of the plug neck from FIG. 2 duringrefueling venting;

FIG. 5 illustrates the plug neck from FIG. 4 following adaptation to arefueling device with suction removal; and

FIG. 6 illustrates a second embodiment of the plug neck according to theinvention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIG. 1 shows a filler neck 1 for a fuel tank of a motor vehicle with twocompensation chambers 2, 3 and a plug neck 4. The plug neck 4 has a ventvalve 5 which is connected to the two compensation chambers 2, 3.Furthermore, a roll-over valve 6 is connected to the plug neck 4. Thevent valve 5 and the roll-over valve 6 are each connected to anactivated carbon filter (not illustrated). On the top side, the plugneck 4 has a closure cover 7.

FIG. 2 illustrates the plug neck 4 from FIG. 1 in an enlarged view fromabove. It can be seen here that a first compensation chamber 2 has achannel 20 routed to the plug neck 4, while the second compensationchamber 3 adjoins the plug neck 4 directly.

FIG. 3 shows the plug neck 4 from FIG. 2 in a sectional illustrationalong line III—III. The plug neck 4 and the filler neck 1 have a commoncentral refueling channel 23. The plug neck 4 has a flange 8 forabutment against flanges 9, 10 of the compensation tanks 2, 3 and of thefiller neck 1. Arranged in the refueling channel 23 is a flap 12 whichcan be pivoted about a pin 11 arranged perpendicularly to the plane ofthe drawing. Said flap 12 serves for pivoting an eccentric 13 whichbutts against a closure element 14 of the vent valve. The eccentric 13is prestressed by a leg spring 15 against the flap 12 and retains thelatter in the horizontal position depicted. A spring 16 is located onthat side of the closure element 14 which is located opposite theeccentric 13. The spring 16 prestresses the closure element 14 into theposition depicted. This position characterizes operational venting, inwhich fuel vapors can overflow from the second compensation chamber 3into the refueling channel 23. For clarification purposes, the flowpaths of the fuel vapors are illustrated by arrows. Of course, it isalso possible for the fuel vapors to overflow in the opposite direction.The vent valve 5 has a cap 17 with a connection neck 18 from which aline (not illustrated specifically) leads to the activated carbonfilter. In the case of operational venting, the closure element 14 ofthe vent valve 5 butts against a valve seat 19 and blocks a connectionof the connection neck 18 of the cap 17 to the first compensationchamber 2.

FIG. 4 illustrates a section through the plug neck with released throughflow of the refueling channel 23 for removal of gases by suction whichdoes not take place through the refueling channel. Unlike FIG. 3, FIG. 4shows the vent valve 5 in an offset section through the channel 20illustrated in FIG. 2. The channel 20 is routed up to just in front ofthe refueling channel 23. In this region, the compensation chambers 2, 3are not connected to the refueling channel 23. The closure element 14 isprestressed to the left here, counter to the force of the spring 16, andis located in a position in which it is remote from the valve seat 19.At the same time, the closure element 14 blocks the connection of therefueling channel 23 to the second compensation chamber 3. This preventsfuel from passing into the second compensation chamber 3 and into therefueling channel 23 during refueling. During refueling of the fueltank, gases can be discharged from the first compensation chamber 2, viathe connection neck 18 of the cap 17, to the activated carbon filter.This configuration of the plug neck 4 is thus suitable for refuelingdevices in the case of which no gases are removed from the refuelingchannel 23 by suction during refueling.

FIG. 5 shows the plug neck 4 from FIG. 4 following adaptation to arefueling device in the case of which gases displaced by the inflowingfuel are removed from the refueling channel 23 by suction. In this case,the vent valve 5 has a cap 21 without a connection neck. Furthermore,the channel 20 illustrated in FIG. 4 is adjoined by a connecting channel22, which is routed into the refueling channel 23. The connectingchannel 22 is configured as a depression in the flange 8 and can easilybe produced, during production of the plug neck 4 from plastic, by aninsert which produces the connecting channel 22 being positioned in aninjection mold. This connects the first compensation chamber 2permanently to the refueling channel 23. The operational venting takesplace here as illustrated in FIG. 3. FIG. 6 shows a plug neck 24 in thecase of which a connecting channel 25, concealed by a covering 26, isarranged on a vent valve 28. The connecting channel 25 connects thefirst compensation chamber 2 to the refueling channel 23. In accordancewith the envisaged application case of the plug neck 4, the connectingchannel 25 may be closed by a closure plug 27 arranged on a covering.The plug 27 is illustrated by chain-dotted lines in the drawing.

We claim:
 1. A plug neck for a filler neck of a fuel tank of a motorvehicle, comprising: a flap arranged in a refueling channel such that itis movable during refueling and for switching a vent valve; a firstcompensation chamber connected to the vent valve for refueling venting;a second compensation chamber connected to the vent valve foroperational venting; wherein the vent valve connects the secondcompensation chamber to the refueling channel during operation; andfurther comprising an exchanging means for alternate connection of thefirst compensation chamber via a switchover valve to a filter when usedwith a non-suction fueling device or the refueling channel when usedwith a suction refueling device for removing vapors.
 2. The plug neck asclaimed in claim 1, wherein the exchanging means for connecting thefirst compensation chamber to the filter has a cap with a connectionneck.
 3. The plug neck as claimed in claim 1, wherein the exchangingmeans for connecting the first compensation chamber to the refuelingchannel has a connecting channel which can be closed by a closure pluglocated between the first compensation chamber and the refuelingchannel.
 4. The plug neck as claimed in claim 1, wherein a closureelement of the vent valve is prestressed against an eccentric which canbe moved by the flap.
 5. The plug neck as claimed in claim 1, furthercomprising a connecting channel arranged outside of the vent valve forproviding a path to the filter.
 6. The plug neck as claimed in claim 5,where the connecting channel is a depression in a flange that connectsthe vent valve to the compensation chambers.
 7. The plug neck as claimedin claim 1, further comprising a connection for a roll-over valve.